The rapid growth in the number of users of mobile communications means that many operators must find new ways of increasing the capacity of their networks. Their options include allocating more frequency, introducing frequency-hopping techniques, and adding microcells and adaptive antenna systems. The introduction of new frequency bands at 1800 and 1900 MHz is an example of allocating frequency...

this paper presents an e-ring shaped printed monopole antenna for uwb applications with dual notched bands performance. in order to generate single frequency band notch function, we applied a u-ring shaped monopole antenna, and by inserting a rectangular ring in the centre of it an e-ring shaped radiating patch created and a dual band-notch function can be achieved. the measured bandwidth of th...

This paper presents a new architecture for an AlGaN/GaN HEMT frequency doubler using the active integrated antenna design approach. A microstrip patch antenna designed at the second harmonic is integrated with the HEMT. The antenna operates as a fundamental frequency reflector in this circuit. Using AlGaN/GaN with 1mm gate periphery, a 4 8 GHz frequency doubler was designed by the suggested des...

in this paper, a resonant slotted waveguide array antenna with circular boundary has been designed and simulated for mono-pulse airborne radar applications. the antenna parameters are:11% bandwidth in x-band (8.6-9.6ghz),vswr < 2, 38dbi directivity, sidelobes level of - 20db and 3-db beam-widths of 2.1degree. to design this antenna, it is divided into short sections (sub-arrays) each with a uni...

this paper presents the results of a study on the radiation characteristics of a plasma triangular antenna in the vhf band (30-300mhz) applying the method of moment. deriving the current distribution of the antenna, it shows the relationship between radiation characteristics of the plasma antenna and the plasma parameters. both theoretical and numerical results indicate that if the plasma frequ...